1. Field of the Invention
The invention relates in general to mobile lifting devices, and more particularly, to a mobile lifting device having: (a) a supporting carriage which is capable of travelling along a specific path; (b) a lifting platform for receiving a load; (c) a hoisting apparatus which has at least two traction means and with the aid of which the lifting platform can be moved with a vertical component of direction in relation to the supporting carriage; (d) a stabilising apparatus which prevents an uncontrolled lateral movement of the lifting platform in relation to the supporting carriage.
2. Background Art
Lifting devices of this kind are used in the most varied technical fields. They are particularly often to be found in enamelling installations in which the objects to be enamelled have to be immersed in treatment tanks, or for instance in the shell assembly or final assembly of vehicle bodies. However, they may also be used, for example, as storage and retrieval units for high-bay warehouses. What is common to all these applications is that the objects have to execute both a translatory (horizontal) movement and also a vertical movement.
From the construction point of view, the simplest way of raising or lowering a lifting platform consists in suspending the latter from a number of cables or chains, generally four, and varying the effective length of the cables or chains by winding them onto or off driven drums in the appropriate manner. At this point, however, the problem arises that the lifting platform may execute uncontrolled lateral movements when acted upon by external lateral forces as well as by lateral forces of inertia, and may start to swing, particularly in the lateral direction. In this connection, the term “lateral” is understood to mean any direction that deviates from the vertical, whether it be in the direction of movement of the lifting device or perpendicular to said direction. In known mobile lifting devices of the kind initially mentioned, therefore, stabilising apparatuses are provided which are intended to eliminate lateral movements of this kind.
There are known from the market, for example, mobile lifting devices in which the stabilising apparatus is formed by scissor-type lattices which are attached to the supporting carriage at the top and to the lifting platform at the bottom. These scissor-type lattices ensure that the lifting platform hanging from the cables or chains possesses no lateral degrees of freedom of movement.
In the case of the lifting device described in EP 1 106 563 A2, which likewise belongs to the kind initially mentioned, stabilisation of the lifting platform against unwanted lateral movements takes place as a result of special guidance of the cables or chains between the supporting carriage and the lifting platform.
Both the abovementioned examples of mobile lifting stations possess a relatively expensive construction.
The object of the present invention is to configure a mobile lifting device of the initially mentioned kind in such a way that the expenditure on construction is reduced.